IL-7 is expressed and secreted by human skeletal muscle cells
| Autor: | Henrik Lian, Bjørn Steen Skålhegg, Andreas J. Wensaas, Frode Norheim, Ole Berg, Svein Dueland, Christian A. Drevon, Truls Raastad, Fred Haugen, Ane Funderud |
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| Rok vydání: | 2010 |
| Předmět: |
Adult
Male medicine.medical_specialty Satellite Cells Skeletal Muscle Physiology Cellular differentiation Muscle Fibers Skeletal Biology Muscle Development Multinucleate Internal medicine Myosin medicine Myocyte Humans RNA Messenger Myogenin Cells Cultured Cell Proliferation Receptors Interleukin-7 Myosin Heavy Chains Myogenesis Cell growth Interleukin-7 Skeletal muscle Cell Differentiation Resistance Training Cell Biology Middle Aged Cell biology Culture Media medicine.anatomical_structure Endocrinology Biomarkers |
| Zdroj: | American journal of physiology. Cell physiology. 298(4) |
| ISSN: | 1522-1563 |
| Popis: | In addition to generating movement, skeletal muscle may have a function as a secretory organ. The aim of the present study was to identify novel proteins with signaling capabilities secreted from skeletal muscle cells. IL-7 was detected in media conditioned by primary cultures of human myotubes differentiated from satellite cells, and concentrations increased with incubation time. By immunoblotting and real-time RT-PCR IL-7 expression was confirmed at both protein and mRNA levels. Furthermore, with immunofluorescence and specific antisera, multinucleated myotubes were found to coexpress IL-7 and myosin heavy chain. During differentiation of human myotubes from satellite cells, IL-7 expression increased at mRNA and protein levels. In contrast, mRNA expression of the IL-7 receptor was 80% lower in myotubes compared with satellite cells. Incubations with recombinant IL-7 under differentiation conditions caused ∼35% reduction in mRNA for the terminal myogenic markers myosin heavy chain 2 (MYH2) and myogenin (MYOG), suggesting that IL-7 may act on satellite cells to inhibit development of the muscle fiber phenotype. Alternative routes of cell development were investigated, and IL-7 increased migration of satellite cells by 40% after 48 h in a Transwell system, whereas cell proliferation remained unchanged. In vivo, real-time RT-PCR analysis of musculus vastus lateralis ( n = 10) and musculus trapezius ( n = 7) biopsies taken from male individuals undergoing a strength training program demonstrated that after 11 wk mean IL-7 mRNA increased by threefold ( P = 0.01) and fourfold ( P = 0.04), respectively. In conclusion, we have demonstrated that IL-7 is a novel myokine regulated both in vitro and in vivo, and it may play a role in the regulation of muscle cell development. |
| Databáze: | OpenAIRE |
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